The present invention relates generally to incubator units or culture chambers as used for performing laboratory experiments under controlled conditions, such as culture growth, radioactive protein-labelling experiments, in vitro fertilization and the like. In such incubator units, gas concentrations, humidity and temperature can be controlled to fit experimental needs.
U.S. Pat. No. 3,886,047 of Billups, Jr. describes a relatively small culture or incubator chamber having a circular base and smoothly rounded concave lid releasably secured together by a single locking ring. One or more flat perforated trays are stacked in the chamber for supporting culture plates, culture flasks, petri dishes and the like. The chamber has an inlet and outlet for flushing with gas between experiments. This provides an inexpensive, independent incubator unit for performing experiments in isolation, eliminating cross-contamination.
When radioactive protein-labelling experiments are performed in larger, continuous flow incubators, extensive contamination problems arise. This is because radioactive .sup.35 S gases are released in such experiments, contaminating the interior of the culture chamber and also being released into the laboratory environment, both due to exhaust of gases continuously flowing through the chamber during the experiment, and also when the chamber is opened at the end of the experiment. Thus, radioactive labelling experiments give rise to significant equipment contamination as well as air contamination, producing potential health hazards to laboratory personnel and possible contamination of subsequent experiments. It is both expensive and time consuming to de-contaminate incubators using traditional techniques. Simply placing charcoal filters in the vents of incubators, as has been done in the past, will cut down on the outside air contamination but contamination within the chamber will still occur.